All categories

4 years ago

Cos²x - 2 sin²x = -2 .Help me to solve it

Mathematics

1 answer:

Alex777 [14]4 years ago

7 0

Step-by-step explanation:

note that

sin²x = (1-cos²x)

LHS= cos²x - 2 sin²x

= cos²x - 2(1-cos²x)

= cos²x - 2 + 2cos²x

= 3cos²x - 2

cos²x = (1-sin²x)

LHS= cos²x - 2 sin²x

=1-sin²x - 2 sin²x

= 1-3sin²x

You might be interested in

Find the value of a square + b square when a+b = 8 and ab = 10

Ne4ueva [31]

As we know,

$\boxed{ \boxed{(a + b) {}^{2} = {a}^{2} + {b}^{2} + 2ab}}$

now, let's plug the given values to find a² + b²

$(8) {}^{2} = {a}^{2} + {b}^{2} + (2 \times 10)$

$64 = {a}^{2} + {b}^{2} + 20$

${a}^{2} + {b}^{2} = 64 - 20$

$a {}^{2} + b {}^{2} = 44$

5 0

3 years ago

Solve for x.

denis-greek [22]

Answer:

$\frac{3\±\sqrt{3}}{3}$

Step-by-step explanation:

Whe have the function $3x^2-6x+2=0$

To solve this equation we must factor.

To factor, we need to find the points where the function is equal to zero. So we use the quadratic formula

$\frac{-b\±\sqrt{b^2-4ac}}{2a}$

Where:

a = 3

b = -6

c = 2

Then

$\frac{-(-6) + \sqrt{(-6)^2-4(3)(2)}}{2(3)} = \frac{3+\sqrt{3}}{3}\\\\and\\\\\frac{-(-6) - \sqrt{(-6)^2-4(3)(2)}}{2(3)}= \frac{3-\sqrt{3}}{3}$

finally the correct answer is $\frac{3\±\sqrt{3}}{3}$

5 0

3 years ago

Read 2 more answers

Three applications for admission to a local university are checked to determine whether each applicant is male or female. The nu

MAVERICK [17]

Answer:87

Step-by-step explanation:

ITS THE MONSTER MASH

4 0

3 years ago

1.<br> Use the formula 2x + 3y = 6 to find y when x=0

Ulleksa [173]

Answer: 4/3

Step-by-step explanation:

You would find this answer because if x is 0 then it is just 2 then when you multiply 3 x 4/3 you get 4 then when you add that by two you get 6

Hopes this helps

5 0

3 years ago

Read 2 more answers

Which of the following is an x-intercept of the function, f(x) = x® + 3х2 – 10x – 24?

azamat

Answer:

so adorable and cities what's not dogs dissatisfied as of plan

4 0

3 years ago

Read 2 more answers

Cos²x - 2 sin²x = -2 .Help me to solve it ​

Cos²x - 2 sin²x = -2 .Help me to solve it